/**
 * DataCleaner (community edition)
 * Copyright (C) 2014 Free Software Foundation, Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.datacleaner.job.concurrent;

import org.datacleaner.api.OutputRowCollector;
import org.datacleaner.job.AbstractOutputRowCollector;

/**
 * Thread local implementation of the {@link OutputRowCollector} interface.
 *
 * This implementation holds a listener which recieves the values that are put
 * to the collector. Consumers should register a listener and remove it after
 * invocation.
 */
public class ThreadLocalOutputRowCollector extends AbstractOutputRowCollector {

    /**
     * Listener interface to be implemented by users of the output row
     * collector.
     */
    public interface Listener {

        void onValues(Object[] values);

    }

    private final ThreadLocal<Listener> _listener;

    public ThreadLocalOutputRowCollector() {
        _listener = new ThreadLocal<>();
    }

    public void setListener(final Listener listener) {
        _listener.set(listener);
    }

    public void removeListener() {
        _listener.remove();
    }

    @Override
    public void putValues(final Object... values) {
        final Listener listener = _listener.get();
        if (listener == null) {
            throw new IllegalStateException("No thread local listener registered!");
        }
        listener.onValues(values);
    }

}
